GIS Data

The backbone of GIS is good data. Inaccurate data can result in inaccurate models and maps, skewing the results of your analysis and ultimately resulting in poor decisions. "Garbage in, garbage out," as the adage says.

The past 10 years has seen an explosion in the amount of data available, much of it free, with the advent of the Internet and proliferation of commercial sources of data. Internet mapping and Web services technology has made it possible for anyone anywhere to share or access data from around the globe.

This wide availability makes it critical to understand what GIS data is, how it is used, and how to select the right data for your needs.